Hokkaido University Research Profiles


Development of Structural Materials for Fusion and High Energy Reactors

Iron-based composites with high thermal conductivity

By appropriately arranging high thermal conductive materials in iron-based structural materials, the thermal conductivity of the entire structural materials can be dramatically improved. This will lead to the improvement of the efficiency of energy production and the reduction of radioactive waste, as well as the development of iron-based structural materials for fusion reactors and high energy reactor divertors, for which there has been no solution so far.

Content of research

This paper focuses on the low thermal conductivity of iron-based materials, which are expected to be used in actual DEMO reactors, with a view to the development of heat exchange devices facing to the plasma in operation, and is aimed at a significant improvement of thermal conductivity, which is considered to be the key to success. The 500°C temperature gradient near the cooling tube of the DEMO reactor divertor imposes a huge heat load that has never been experienced in engineering equipment before. On various iron-based materials (pure iron, reduced activation ferritic martensitic steel and oxide dispersion strengthened ferritic steel), Cu and W wires of high thermal conductivity are appropriately arranged to ensure strength as a structural material while serving as a heat sink.

  • Conceptual diagram of a demonstration fusion reactor (DEMO reactor) and a heat exchange device (divertor)

Potential for social implementation

  • At present, the International Thermonuclear Experimental Reactor (ITER) is under construction, and a demonstration reactor with high thermal neutron load is being designed in parallel. If the proposed new high-performance materials are developed and the stable operation of this demonstration reactor is proven, the energy problem will be solved semi-permanently.

Appealing points to industry and local governments

The production of steel composites with high thermal conductivity to be developed in this research involves complex processes such as powder metallurgy, plasma sintering, high-pressure sintering, extrusion molding and heat treatment, and requires precise and advanced technology at each stage. Therefore, the cooperation of engineers who are familiar with these processes and joint research with related organizations are essential.